The present invention relates to alternating current (AC) driven motorized wheel assemblies that propel and retard off-highway vehicles.
In conventional direct current (DC) motorized wheel assemblies, DC motor rotors use a commutator upon which carbon brushes are held in position with brush holders attached to the motor to maintain a sliding contact and thus allow electrical power to be fed into the rotor for torque production. The brushes and commutator are high maintenance parts of the DC motor and need to be readily accessible for regular replacement and service. Therefore, DC motors are often positioned in the center of the tires with commutators at the outboard end for easy maintenance access to the brushes and removal of the rotor. Since the magnet frame of the DC motor is thick steel, it serves as both the motor frame structure and the wheel frame structure. However, locating the motor in the center of the tire limits the maximum diameter of the rotor and thus puts severe limits on the maximum power capability of the motor.
With conventional DC motors, a hollow cylinder (an axle box) provides a mounting structure for the wheels and serves as an air plenum for cooling air for the wheel motors which originates from remote blowers and exits through the wheels.